I read a book called the Hunt For Bin Ladin by Robin Moore a few years ago. In it, he wrote about the difficulties the Special Forces Teams were having with Helicopter extractions in the mountains. One method they developed was to carry a huge fuel bladder with them. When they landed, they would kick out the fuel bladder, pump all of the Helicopter's fuel into it, then take-off tethered to the bladder. After take-off they would pump the fuel back into the aircraft, retract the bladder, and be on their way. This is the first I had ever heard of anything like that. Amazing.

-Steve G.